Let's say you're a terrorist organization... The "law" can track what you're communicating, what you're doing, to some extent. They probably hear your phone calls and read your emails, since both are suspicious or have been suspicious. They follow you, mister suspicious-pants, around. They don't want you blowing anything up.

But your goal is to blow shit up. And you're good at it. You want to get together with your friends and blow all the shit up. You want to, I dunno, smuggle in a nuclear bomb or a sizeable amount of chemical weapons to be distributed by toy aeroplanes.

So, what do you do?

You blow up a few subway cars.